X-ray-tube regulator



A N LUCIAN X-RAY TUBE REGUQATOR Filed Obt. '11. 1920 Oct. 19 1926.

Patented Oct. 19, 1-926.

UNITED STATES ARSENE N. LUCIAN, OF PHILADELPHIA, PENN SYLVAIIIA.

X-RAY-TUBE REGULATOR.

Application filed October 11, 1920. Serial No. 416,089.

This invention relates to X-ray tubes. The object of the invention is toimprove both the regulation and the operation of a tube of the gas type.

The proper operation of a tube of this type requires the maintenance ofa critical degree of vacuum within the tube. From continuous service thevacuum tends to rise, that is, the pressure within 'thebulb de creasesduring service and it-is necessary that some means be provided forlowering the vacuum to the critical point necessary for proper operationin order that a continuance in the service of the tube may immediatelybe bad. This regulation of the vacuum within a tube is accomplishedthrough the medium of a side tube provided with a spark electrode incontact with a gas emitting chemical customarily held in place by meansof a stuffing of asbestos. In some instances a packing of abscstos insuch a side tube has been employed without other chemical. The passageof sparks from the auxiliary electrode in this side tube causes gas tobe emitted not only from the chemical charge but also from the asbestospacking which escapes into the interior of the bulb to lower the vacuum.It has been found that, when asbestos has been employed to keep the chemical charge in place, that the emitted gas is for the most partinjurious to an X-ray tube as it contains a number of impuritiesparticularly organic vapors and oxygen developed from the asbestos.Ideally that particular gas alone should be employed for reducing thevacuum after a continuous run of a tube which gas is the same as thatformin the attenuated atmosphere within the bu b proper.

It is an object of my invention to provide a regulator which upon properexcitation will supply the desired quantity of only the desired gaswhich alone may enter the bulb proper to regulate'the vacuum and Icontemplate the provision of means which shall revent the loosening ofany impurities durmg the regulating operation or at any time. A furtherobject of'my invention is to improve the general structure of a tube, asto the mounting of the electrodes and the provision of a self containedvalve to facilitate the operation of the tube in response tonon-uni-directional potential impulses.

The above will better be understood by reference to the illustrativeembodiments described in the following specification in conwith partsshown in elevation of an illus- .trative embodiment of my invention;

Fig. 2 is a detail section drawn to an enlarged scale of my regulatorstructure; and

Fig. 3 is a similar view showing a modification of my regulatorstructure.

A is a glass bulb of usual construction having opposite alignedelectrode extensions 1 and 2. Sealedto the far end of extensipn l is aninner glass sleeve 3 mounting the pinch slip-sleeve 4 of cathode 5 whichhas a substantial metallic stem 6, extending outwardly within the sleeve3 and is connected with the terminal electrode 7. The sleeve 3 ispreferably provided with vents 8.

Sealed to the extension 1, preferably some what inward from its outerend but near its outer end, is a glass sleeve 9 which projects inwardlytowards the interior of bulb A and is provided with a bulbousenlargement 10 having ,vents 11 near the mouth of the extension 1. Thesleeve 9 terminates in a throat 12 having bosses 13 cooperating withperforations 1 1, in the slotted metal mounting sleeve 15 for anode 16.The anode 16 being mounted upon the last sleeve 15 is thereforeelectrically insulated so far as con duction is concerned from all otherparts of the tube.

An auxiliary electrode, which may be identical in construction with thecathode 5 and symmetrically positioned with respect thereto, isindicated by 17, which has an outwardly extending substantial sizedmetal stem 18 extending within the glass sleeve 19 which is sealed tothe outer end of extension 1 and is connected with the anode terminal20.

The sleeve 19, like the sleeve 3 may have vents 21. The auxiliaryelectrode 17, cooperatingwith the rear 22 of anode 16 serves as adirection valve for the entire tube and the bulbous enlargement 10localizes the valve action so that no interference with the X-raygeneration of the tube is permitted. Heretofore it has been customary toconnect a valve tube in series with the ordinary. I

X-ray tube for the purpose of suppressing inverse, but with myconstruction. the valve and the X-ray tube are eonibined'within one bulbso that a saving is accomplished. In my tube the X-ray' anode serves theadditional function of an electrode for the valve formed between itselfand the electrode 17.

For regulating the vacuum within the tube the usual side tube B isprovided, in the outer end of which is sealed mounting glass sleeve 30which mounts the split expansion metallic sleeve 31 connected with thespark terminal 32. The sleeve 31 is preferably spun. out into a collar33 serving as a shoulder mounting for the metallic pan 3% which has aflange 35 serving to grip the vitreous porous thimble 36. In theembodiment shown in Fig. l the flange 35 directly grips the rim of thethimble 36, whereas in Fig. 2 it is shown secured thereto by a suitablevitreous cement 37 such as alundum paste. Projecting through the pan 34into the interior of the thimble 36 is electrode 38, preferably providedwith a number of flaring wires or fingers 39 projecting into thechemical charge 4:0. In Fig. 3 the pan 41 corresponding to the pan 34has a spring flange 4E2, tending to expand and frictiona'lly engage theinner surface of the rim of the thimble 36. is a conducting Wire sealedtight in thimble 36.

I prefer to construct my thimble 36 out of some highly porous earthenmaterial which itself is free from gases and which under electricexcitation will not decompose into gas. I prefer that the material behighly refractory and that it be impervious to the passage of all solidmaterial but shall permit the passage through its walls of gas which maybe generated by the chemical charge 40 within its cavity. I have foundthat unglazed porcelain, alundum and carborundum are satisfactorymaterials for the construction of the porous thimble, 36. The chemicalcharge L0 may consist of any chemical capable under electric excitationof liberating the gas desired for the atmosphere within the bulb A.Examples for the liberation of nitrogen areiron-nitride,aluminum-nitride and calcium-nitride and for the liberation ofcarbondioxideferrous oxalate, ferrous carbonate and manganesiumcarbonate. The charge 40 is completely enclosed so that no looseparticles may be driven out into the bulb A although the generated gasmay freely pass through the porous walls of the thimble. Although thisporous structure is shown in the form of a thimble, porous throughout, Icontemplate that every portion thereof so functions. The side walls -13are in the form of a sleeve which is insulating, refractory and porousand which serves as a protector for the electrode 38. I believe that theuse of such a sleeve is broadly new. I also understand that the end Wall44 of my thimble may be regarded as the sole functioning porous wall ofmy structure.

In other words, functionally, I contemplate the complete enclosure ofthe gas emitting charge of chemical by an enclosure at least a portionof the walls of which are porous to the passage of the desired gas butimpervlous. to the passage of undesirable substances during theregulation of the tube and in fact at all times.

What I claim and desire to secure by U. S. Letters Patent is:

1. An X-ray tube having a vacuum regulator comprising an auxiliaryterminal; a charge capable of emitting a gas under excitation from saidterminal and located at the end of said terminal in communication with acavity of said X-ray tube; anda structure completely out of contact withthe glass walls of said tube and completely enclosing said charge andhaving a solid Wall of porous material dividing said charge from thecavity of said X-ray tube.

2. In an X-ray tube, an electrode and a hollow cylindrical sleeve ofsolid insulating porous material cooperating with said electrode andpermitting the assage of gas therethrough but insulating fioth to thepassage of electricity and of solid particles.

3. A regulator for X-ray tubes comprising a porous thimble of insulatingrefractory material; a gas emitting chemical within said thimble; anelectrode in cooperative relation to said chemical to excite the same toemit gas; and means for completing with said thimble a completeenclosure about said chemical.

In witness whereof I have signed my name to this specification this 20thday of August, 1920.

ARSENE N. LUCIAN.

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